Lesson of the Month - Comparative expression of calretinin in selected odontogenic tumours: a possible relationship to histogenesis

Aims: Calretinin, a calcium-binding protein, is expressed primarily in certain subtypes of neurons. It has also been reported to be present in mesotheliomas and other tumours. The aim was to determine the expression of calretinin in selected odontogenic neoplasms. Methods and results: Immunohistochemistry for calretinin was performed on 55 odontogenic tumours consisting of 20 solid ameloblastomas, five calcifying epithelial odontogenic tumours, 10 adenomatoid odontogenic tumours, 10 ameloblastic fibromas and 10 odontogenic myxomas. The distribution, intensity, pattern and localization of immunoreactive cells were determined by conventional light microscopy. chi(2) test was used for statistical analysis and P < 0.05 was considered to be significant. All 20 ameloblastomas showed intense immunopositivity with a diffuse distribution pattern. None of the other neoplasms was reactive with calretinin. Differences in the proportion of calretinin expression between groups were statistically significant at P < 0.001. Conclusions: Considering that ameloblastomas, in contrast to the other studied tumours, were consistently reactive for calretinin, this protein may have a role in the pathogenesis of this aggressive neoplasm.